FWIW, we discovered this time 2 years ago (IIRC) that the out-pipe for our bath had been leaking on to the concrete floor below for years and the concrete was saturated, causing mushrooms to grow in the antique plywood later under our lino and strange crystal formations to develop on the concrete under the kitchen cupboards in the next room. After fixing the problem and a year of letting the house dry out it doesn't seem to have caused any lasting issues. Fingers crossed, etc.

Also probably depends on where your damp proof course is? Below the damp proof course, I assume it's designed to deal with a fair bit of moisture. Above the damp proof course, it's probably less fun but I am guessing an acute exposure is less bad than a chronic one?